/Engine/Source/Runtime/InteractiveToolsFramework/Public/BaseGizmos/GizmoElementBase.h
View-dependent angle tolerance in radians For Axis, object is culled when angle between view dependent axis and view direction is less than tolerance angle. For Planar, cos of angle between view dependent axis (plane normal) and view direction. When the view direction is within this tolerance from the plane or axis, this object will be culled.
virtual void SetViewDependentAngleTol ( float InMaxAngleTol )